Drilling mud by-pass for rotary drill bits



July 12, 1960 v w. D.YMYl-:Rs 2,944,794

' DRILLING MUD BY-PAss RoR ROTARY DRILL/BITS Filed sept. so. i957 rfaeA/IKS:

United States. PatentA 2,944,794 DRILLING MUD BY-PASS FOR ROTARY DRILL BITS William Myers, Norwalk, Calif., assignor, by mesne assignments, to Houston Oil Field Material Company, Inc., Houston, Tex., a corporation of Delaware Filed Sept. so, 1957, ser. No. 681,216

Claims. (Cl. Z55-24) The .presentinvention relates to the drillingof well bores bythe rotary method, inv which drilling mud 1s circulated through the drilling string and drill bit for the primaryf purposeof removing the cuttings rproduced by the drill bit and tlushing them to the top ofjthe well bore.V f L;

Rotary drill :bits employedl in the drilling of well boresrnayV contain nozzles or outlet openings of relatively s`rnall area for the purposeof discharging drilling -uid at a'hgh velocity directly toward the bottom of the hole, the drill bitfcutters, or both;` The smallfarea'of the openings in `the drill bit nozzles restricts the ow of the drilling mud in the well bore intothetubular drilling string while it is being lowered within the well bore. The restricted openings 'through whichl the drilling mud must pass may result inv damage tothe formation caused by the drillingstring and bitfunctioning as a giant piston as they'are lowered in the well bore, 'which builds up a comparativelyhigh pressure in the drilling mud and forces it into the formation.v The restricted fluid circulation area throughthe drill bit also decreasesV the ease with which the drilling mud can drain vfrom the drill pipe or other tubular drilling string when it is being removed from the well bore; The result is often the spillingof the drilling mud on the deirick iloor when each stand of; drill pipe is disconnot to be Vtaken in a limiting sense,since the scope of the invention is best defined by the appended claims.

- Referring to the drawings:

Figure l is a combined longitudinal section 'and side elevation of an apparatusvbeing moved in a well bore;

Fig. 2 is an enlarged fragmentary section of part of the apparatus shown in Fig. l;

Fig. 3 is a side elevation, as seen from the right of Fig. 2.

'Ihe apparatus illustrated in the drawings includes a rotary drill bit A of any suitable type connected to the lowerendof a string of drill pipe B, or corresponding tubular drilling string, extending to the top of the well bore C.- As is well known, the string of drill pipe is rotated to rotate the drill bit in accomplishingthe drilling operation, the drill bit cutters 10 operating upon the bottom of the -Well bore while drilling mud is being pumped'down through the drillingfstn'ng and through the nozzle or nozzles 11 in the drill bit'for the purpose L of removing the cuttings and flushing them around the However, during the actual drilling; operation `the fluidV being Ypumped down through thedrillstring closes the by-pass device C/to cause all ofthe drilling lluid to pass throughjthe drill bit Vnozzlesrllforthe purpose of maintaining the'bottom o the hole and the 'drill bit cutters v10 free and-clean of cuttings.A

f As-Y disclosed,v the by-passf apparatus C includes a tubular body 15 which may have a lower threaded box 16 threadedly attached to, the upper pin end 17 of the bit body 18, The upper end of the tubular body may be Y "constituted as athreaded pin 19 threadedly `secured to nected;.1 In `some instances, itresults in the drill pipe performing a swabbing actioninthe well bore while being elevated therein, with the hazard of Vproducing a blow-out. Y

f An object of the invention is to provide an improved apparatus which enables the fluid in'the well bore Vto by-v pass around the drill'bit into the drilling stringV` as the latter is being lowered in the well bore and-also'while the drilling string is' being. elevatedtherewithim such by-passing being prevented during -thetime drilling iiuid is being pumpeddownwardlythroughthedrillv string.

By.' employing 'suchan apparatus,4 highpressure in the well bores cannot be developed Aas-a result of lowering the drillstring therewithin, nor will the'driljling string during its elevation in the well bore.` s Another object of `the`invention is to provide an apparatus ofthe character indicatedwhich has a substantially unobstructed passagetherethrough so as'to Vavoid swabthe well bore 'ortend to retain ;tl iedrillingY -fluid impedance to the liowjof` drilling Ifluid down through Ythe drilling'string during thedrilling operation.A

A further object of the invention is :to provide a fluid vby-pass apparatus in a drilling string which is of simple construction, economical to manufacture, and easy to maintain in proper operating condition. f 1

This invention vpossesses many otheradvantages, and has other objects-which may be made more clearly apparentv from a consideration of a form in which it may be emboddied. ThisV vform is shown in the drawings accompanying and forming part of the present specification. It Vwill .nowbe described in detail, forthe purpose of "illustrating"`the`general principles of the' invention; but

the box portion 20 of a drill pipe section or drill. collar thereabove,wl1ich forms part of the drillingfstring B extendingto the' top of the'hole. l -Y The" tubular body hasfa plurality of valve controlled Alateral passages or ports A21 therein through which fluid vcan pass. Such passages or ports will be closed in response to the pressure of the fluid being pumped down through the string of vdrillpipe B and out through the drill bit A.; As illustrated, each passage or port 21-is formedin a separate removable valve body 22 which has an outer end 23 threadedly secured within a companionthreadednbore 24 through the body, theinner portion of the valve body having a `sideseal25,gsuch' as a rubber O ring, disposed in a body -groove 26 Yand sealingly en'- gaging the wall of theV bore 24. Thebody'22A has an intermediate spider portion 27 defined by circumferentially spaced radial arms28 -extending between the central portion 29 and the outer portion of the body.' Y The' central or hub portion 29 has a passage therethrough slid- `ably receiving .the valve stem 30' of a valve member,

`theinner-portio-n of which is secured to'a valve head the valve stem '30' andengaging the valve head 31l at its inner end and the hub 29 atits outer end. vThe extent oct movement kof the valve head 31 from its s'eat is' limited by engagement of a suitable stop device 34, such asa nut threaded on the outer end of the stem, with the hubf29 When the valve is in open position, iluid can pass freely through thev body passage 21 in both directions between the interior and exterior of the tubular body member.

It is to be noted that the inner portion of the valve body preferably does not extend inwardly of the inner wall 40 of the body 15. Similarly, the yalve head 31, when it engages its companion valve s eat 32, need not project inwardly of the inner wall 40 of-.the body, or the projection is of a relatively minor extent so that there are substantially no obstructions or restrictions to the passage of fluid through the tubular body member 15, or for that matter to the passage of other devices, such as surveying instruments and the like.

The plurality of valve devices is arranged generally radially in the tubular body 15, to provide a total Apassage area that is quite substantial, and which may be much greater than the total area throughl theV drill bit nozzles 11, During the lowering ofthe drilling string B through the drilling mud and other uids in the well bore, the springs '.33 will retain the valve heads 3'1 removed from the valve seats 342. Accordingly, the drilling mud can How into the drill string B through the drill bit nozzles 11-v andalso through the body passages 21, which will permit a comparatively ready ingress of the dnilling mud into the string of drill pipe to lill the same, and thereby avoiding the building up of high pressures in the drilling v mud in the well bore which might be forced into the formation, potentially damaging the latter.

h When the drilling operation is to commence, the drill string B is rotated and the drilling mud pumped downwa'rdly-through it. The pressure of the uid will act upon the valve heads 31 and shift them outwardly against the `force of the springs 33 into seating engagement with the valve seats 32, closing the by-pass passages or ports 21 against outward llow of uid from the tubular body 15. Accordingly, all of the drilling mud being pumped through the tubular string will then pass through the drill bit nozzles 1l, and if such nozzles have a comparatively small area, the uid will issue at a high velocity therefrom for direct action upon the bottom of the well bore, upon the cutters 10, or both, to maintain such regions 4and parts in a clean condition, permitting the cutters to have Vmaximum penetration into the bottom ofthe hole.

When the drill pipe B is to be removed from the well bore, the pumping action ceases and the relieving of the pressure in the well bore will permit the springs 33 to |shift the valve heads l31 inwardly away from theirseats 32, thereby opening the by-pass passages 21. As the drill pipe lis raisedin the well bore, the drilling mud therewithin can drain through the drill bit nozzles 1l. It can also drain readily through the open passages 21 in the tubular body to the Vexterior 'ofthe drill string. The ability of the fluid to drain rapidly from the drill pipe -B will minimize the swabbing action of the'drill string on the drilling mud in the well bore, and will also insure 'that each stand of drill pipe above the rotary table will be empty and free of drilling mud when such stand of drill pipe is disconnected from the drill pipe therebelow, thereby preventing drilling mud from spilling on the der- Arick floor and on the rig equipment.

The springs 33 have sufficient compressive force so as to prevent shifting of the valve heads 3l outwardly into engagement with their seats 32 to close the passages 21 during elevation of the drill pipe in the Well bore. However, the usual pressures encountered during the drilling operation are more than adequate to overcome the .force of .thesprings 3-3 and shift the valve heads outwardlyof the body into sealing engagement with the valve seats I32 to close the by-pass passages 21.

The` inventorv claims:

-.. `l. Indrillingapparatusfor awell bore: a tubular drill fmit'iluidrto flow upwardly therethrough into the drill string during lowering of the drill string yin the well bore flow of diuid; said body having a side port for allowing lluid to dow between the interior and exterior of said body, said body having a valve seat surrounding said port; a valve member movable in a laterally outward direction into engagement with said seat to close said port; and spring means engaging said valve member to shift said valve member laterally inwardly away from said seat; said spring means exerting a force sufficient to maintain said valve member laway from said seat during elevation of said drill string and drill bit in the well bore to permit simultaneous drainage of drilling fluid from said drill string through said port and bit nozzle.

2. In drilling apparatus for a well bore: a tubular drill string -including a tubular body; a drill bit secured to the drill string and having a nozzle for discharging fluid from said drill string, said nozzle being normally open to permit fluid to flow upwardly therethrough into the drill string during lowering of the drill string in the well bore and said drill string being open to permit such upward rlovw of duid; said body having a central passage therethrough; said body having a side port for allowing iluid to flow between the interior and exterior 0f Said body, said bodyV having a valve seat surrounding said port; a valve member movable in a laterally outward direction into engagement with said seat to close said port; and spring means engaging said valve member to shift said valve member laterally inwardly away from said seat; said spring means exerting a force sutlicient to maintain said valve member away from said seat during elevation of said drill string and drill bit in the well bore to permit simultaneous drainage of drilling fluid from said drill string through said port yand bit nozzle; said central passage being substantially free from obstructions when said valve member engages said seat.

3. In drilling apparatus for a'well bore: a tubular drill I string including a tubular body; a drill bit secured to the drill str-ing and having a nozzle for discharging fluid from said drill string, said nozzle being normally open to permit fluid to ow upwardly therethrough into the drill string during lowering of the drill string in the well bore and said drill string being open to permit such upward flow of fluid; said body having a generally radial bore through its wall; la valve body disposed in said bore and having a port therethrough surrounded by an inner valve seat; a valve member movable in a laterally outward direction into engagement with said seat to close said port; and spring means engaging said valve member to shift said valve member laterally inwardly away from said seat; said spring means exerting a force sucient to maintain said valve member away from said seat during elevation of said drill string and drill bit in the well bore to permit simultaneous drainage of drilling iluid from said drill string through said port and bit nozzle.

4. In drilling apparatus for a well bore: a tubular drill string including a tubular body; a drill bit secured to the drill string and having a nozzle for discharging uid from said drill string, said nozzle being normally open to permit fluid to ilow upwardly therethrough into the drill string during lowering of the drill string into the well bore and said drill string being open to permit such upward flow of Huid; said body having a generally radial bore through its wall; a valve body disposed in said bore and-having a port therethrough surrounded by an inner valve seat; a valve stem slidable in said valve body; a valve head secured to said stem and movable in a laterally outward direction into engagement with said seat to close said port; and a spring engaging said valve body and head to urge said head laterally inwardly away from said seat; said spring exerting aforce sucient to maintain said head`away from said seat during elevation of said drill string and drill bit in the well bore to permit simultaneous drainage of drilling uid from said drill string through said port and bit nozzle.

5. In drilling apparatus for a well bore: a tubular drill string including a tubular body; a drill bit secured to the drill string and having a nozzle for discharging uid from said drill string, said nozzle being normally open to permit uid to iow upwardly therethrough into the drill string during lowering of the drill string in the well bore and said drill string being open to permit such upward flow of uid; said body having a central passage therethrough; said body having a generally radial bore though its wall; a valve body disposed in said bore and having a port therethrough surrounded by an inner valve seat, said port establishing communication between said central passage and the exterior of said tubular body; a valve stem slidable in said `valve body; a valve head secured to said stem and movable in a laterally outward direction into engagement with said seat to close said port; a spring engaging said valve body and head to urge said head bit nozzle; said central passage being substantially free4 from obstruction when said valve member engages said seat.

References Cited in the le of this patent UNITED STATES PATENTS 337,236 Briscoe Mar. 2, 1886 1,649,998 Whinnen Nov. 22, 1927 1,918,096 Greve July 1l, 1933 

